DAMASCUS, Syria, Oct. 21 -- A day after its release, a U.N. report that implicated senior Syrian officials in the assassination of former Lebanese prime minister Rafiq Hariri escalated pressure on the already beleaguered government here and ignited renewed demands that Lebanon's pro-Syrian president step down.

The publication of the report on the deaths of Hariri and 22 other people in a car bombing in Beirut on Feb. 14 unleashed a reaction seldom seen in the Middle East. The 54-page document was read in its entirety on al-Jazeera, the Arab satellite television network; other stations broadcast hours of coverage Friday on the report and its fallout. To many people here, its publication marked a turning point in Middle East politics, signaling a looming confrontation with an uncertain outcome.

"This is simply the beginning," said Farid El-Khazen, a Lebanese lawmaker and political scientist. "There is little room for maneuver left for the Syrians now. They have to cooperate fully to save themselves from more isolation or they opt for rejection of the report, claiming it is all political. Syria doesn't have a middle-ground option."

In Damascus, some Syrian government supporters were unusually open in expressing fear about the repercussions of the inquiry, which President Bush cited Friday in calling on the U.N. Security Council to take action.

"The government is rather cornered. Essentially, what the government can do is very limited," said Georges Jabbour, a Syrian legislator and former presidential adviser. "I am not quite optimistic."

The report stopped short of directly blaming President Bashar Assad or members of his inner circle, where his relatives occupy the most sensitive posts. But it bluntly said that the investigation's leads pointed directly at involvement by Syrian security officials in the assassination and insisted that Syria clarify unresolved questions.

The report said Syria's longtime foreign minister, Farouk Charaa, lied in a letter to investigators. It also cited one witness as implicating Assad's powerful brother-in-law, Asef Shawkat. Another claim that Shawkat, Assad's brother Maher and other senior officials played a role in planning the assassination was deleted from the final report.

With a mix of anger and trepidation, Syrian officials condemned the findings, although their response was muted on the Muslim Sabbath. Most hewed to a common line: that the investigation relied on often unnamed witnesses of questionable character, that the report was tailored to meet U.S. objections to Syrian policy and that its findings would never hold up in a court of law. The information minister, Mehdi Dakhlallah, called the investigation "a political statement."

"It is impossible that a fair court would accept a report like this, relying as it does on mere talk," he said in a news release.

The most immediate fallout was growing pressure in Lebanon for the resignation of the country's pro-Syrian president, Emile Lahoud. The president rebuffed demands that he step down in August after four Lebanese generals were arrested on suspicion of participating in the assassination.

The U.N. investigation, led by the German prosecutor Detlev Mehlis, found that Lahoud received a phone call minutes before the blast from the brother of a prominent member of a pro-Syrian group, who in turn called one of the country's generals. Lahoud's office said it categorically denied receiving such a call.

In a signal Lahoud has no intention of resigning, the statement by his office said the charge was part of a months-long campaign against him "and the national responsibilities he shoulders and will continue to do so at this delicate stage in Lebanon's history."

It was an altogether different mood Friday night at the tomb of Hariri, under the shadow of a sprawling, Ottoman-style, blue-domed mosque in downtown Beirut, where hundreds of Lebanese gathered to mark the report's release.

Some prayed by the grave. Others, carrying Lebanese flags, called loudly for Lahoud to resign.

"There is no god but God, and Syria is the enemy of God," some shouted in a chant that usually names Israel or the United States.

"What should happen next is exactly what's happening. People should express themselves," said Reina Sarkis, a 34-year-old therapist. She wore a white T-shirt on which she had scrawled in black, "I love Mehlis," a reference to the U.N. investigator.

To many in Lebanon, Lahoud's stubbornness has left the country's politics in a frustrating limbo. On one side are the forces behind the protests this spring that helped force the end of Syria's 29-year military presence. These forces, while divided, now command a majority in parliament.

On the other side are Lahoud and the still formidable influence that Syria wields through some Lebanese factions and parts of Lebanon's intelligence apparatus. "This president now, he has to resign. We don't have a president of the republic. We have someone who is implicated by a conflict," said Melhem Chaoul, an analyst at Lebanese University. "We need stability, and with him, we don't have stability."

In Lebanon's often Byzantine politics, Lahoud can still draw on factions and institutions that are reluctant to see him go, each for its own reason. Lebanon's most powerful Shiite Muslim movement, Hezbollah, has backed his tenure, as have followers of Michel Aoun, a civil war-era prime minister and member of parliament who is popular among Lebanon's Maronite Christians.

The Mehlis report had become a virtual national obsession in Lebanon, after rumors swirled for weeks over its possible conclusions. The day it was released, a disc jockey at Radio Liban played "What a Wonderful World.".

The response was far more muted in Damascus, where the media have paid scant attention to the investigation. "When was the report released?" asked Majed Natour, a baker kneading dough sprinkled with pistachios at a pastry shop.

Like many people in the city, he was dismissive of the investigation. When told of its findings, he shook his head: It was yet another ploy to benefit Israel, whose interests he said were promoted in the region by the aggressive actions of the United States. "That's my opinion," the 25-year-old said. "Syria is the only country that will say no to them."

Former president Hafez Assad, who died in 2000 after 30 years in power, pursued a skillful foreign policy that gave Syria a political role often exceeding its military or economic might. Tensions flared with the United States, but Syria often delivered just enough.

Under Assad's less seasoned son, the country has found itself perhaps more isolated than at any time in its modern history. The United States has demanded a comprehensive shift in policy -- including cutting support to Hezbollah and radical Palestinian factions and closure of the Iraqi border to infiltration by foreign fighters. Syrian officials point to concrete steps they have taken on the border to arrest would-be insurgents and say the United States has done little on the sections of the Iraqi frontier it controls.

The European Union has delayed signing a trade agreement, a decision Syrians attribute to U.S. pressure. The U.S. ambassador was withdrawn after Hariri's assassination, and visits by senior European officials are rare.

The government itself appears divided between those who believe they can wait the Bush administration out and others who believe only wholesale engagement can break the sense of siege. "Of course, we know really what matters to the United States is Iraq," said Jabbour, the Syrian legislator. "So is there a Syrian-American deal on Iraq? Would Syria help the United States pacify Iraq?

"I don't know."

Special correspondent Alia Ibrahim in Beirut contributed to this report.